The present invention generally relates to connecting elements used, for example, for the attachment of automobile wheels or rims to a motor vehicle by means of wheel bolts. More specifically, the present invention relates to a method for implementing fastener arrangements or screw elements to avoid deformation and damage of the outer and inner surfaces of such connecting elements.
In the case of known fasteners, it is a disadvantage that the outer surface of the screw element and/or the inner surface of the component are frequently deformed and damaged when the screw element is repeatedly screwed in, because the contact of the outer surface of the screw element, depending on the dimensioning of the screw element and the component, occurs either in the region of the front or rear edge, when viewed in the direction in which the screw element is screwed in, of the concavely curved inner surface of the component.
Such deformations cause significant problems during assembly when a defined torque is selected. In addition, with the prevailing final tolerance stack-ups extremely variable load configurations result, namely so-called outer load supports and inner load supports, and thus strongly varying frictional moments result when the head makes contact.
The solutions embodying the principles of the present invention are based on the recognition that the unfavorable forced contact conditions in the region of the front or rear edge, in the direction in which the screw is screwed in, of the concavely curved inner surface of the component, result from the fact that the centers of curvature of the curvature of the outer surface and the curvature of the inner surface are not spaced apart from each other in a direction vertical to the longitudinal axis.
As a result, the contact between the outer surface and the inner surface occurs, when viewed in the direction in which the screw is screwed in, either at a front or a rear edge region of the inner surface. Because of these unfavorable force conditions, deformation and damage of the outer and inner surfaces can occur, which result in an adverse effect on the fastening ability, for example, in the case of a defined torque.
It is desirable to create a fastener arrangement or a screw element of the same kind where the contact surfaces are deformed or damaged as little as possible even if they are loosened or fastened a number of times, and where, in addition, the extreme outer and inner load supports are to be avoided.
A method of connecting elements embodying the principles of this invention is by creating a fastener arrangement, where the contact surfaces in an axial section of the fastener device are defined by arcuate sections curved in such a way, that the center(s) of curvature of the convexly curved outer surface extending in a direction perpendicular to the longitudinal axis is (are) located at such a distance from the center(s) of curvature of the concavely curved inner surface, that the contact surfaces, when they are fastened to each other, are located between the ends of their arc sections.
Furthermore, the above objective is achieved by a screw element according to the principles of this invention, where the contact surfaces are defined, in an axial section of the screw element, by curved arc sections, the centers of curvature of which are located at such a distance from the longitudinal axis that the convexly curved outer surface and the concavely curved inner surface of the component, when they are fastened to each other, are in contact with each other between the ends of their arcuate sections.